Shotgun choke



` June 26, 1951 w. F.scHMEL|NG sHo'rGuN cHoxE Filed Jan. 29, 194,@y

all',

INVENTOR.

Patented June 2,6, 1951 1 UNITED 'STATES PATENT OFFICE l 2 Claims.

l This invention relates to a device to control the pattern and penetrating' power of a charge from a shotgun and has for vits primary object to provide means to permit an expansion of the propelling gas before it leaves the gun muzzle f and to utilize a portion of said gas to control the pattern of a shot string.

Another object of the linvention is to provide a shotgun choke which utilizes a portion of the charge propelling gas to determine the pattern of the charge and which incorporates means to vary the quantity of gas so used.

Still another object of the invention is to provide a shotgun choke having a plurality of flexible, bore-defining fingers which operate to determine the muzzle diameter of the gun, each finger being provided with a gas passage which assists in projectile pattern and velocity control.

Other objects and advantages of the invention will become apparent from the following specification, reference being had to the accompanying drawings in which- V Fig. 1 is a side elevational view of a shotgun choke embodying the invention, shown in position on a gun barrel; Fig. 2 is a central vertical section of the device shown in Fig. 1; Figs. 3, 4, and 5 are sections taken on lines 3 3, 4-4 and 5 5 respectively in Fig. 2; Fig. 6 is a side elevation, with parts broken away, of a pair of nger operating segments; Fig. 7 is an end view of the segments shown in Fig. 6.

Referring to the drawings, the choke constructed in accordance with the present invention is shown attached to a shotgun barrel I0. In the form shown, the-attachment is by means of threads II, although it is apparent that the device may be swaged in place. The choke itself comprises a body I2 having vent ports It in the form of slots in the sides of the body. An inner vent controlling shutter tube I6 is disposed inside the body I2 and is adjustable with respect to the body by threads I8 formed on the shutter sleeve and interiorly of the body. Openings I1 in the tube I6 can be rotated into and out of register with the vents I4 by axial and rotary adjustment of sleeve I6. Adjustment of the shutter sleeve is obtained by rotating a knurled grip to which the shutter sleeve is attached by any suitable means suchA as threads 22. The

threads 22 are normally locked, so that rotation of the grip moves the sleeve in the threads I8. It will be seen that the interior diameter of the body I2 and the tube I6 are enlarged with respect to the gun barrel I0 to form an expansion chamber in which the charge propelling gas can expand for the purpose later set forth.

The grip 20 forms a portion of a coniining cylinder which extends slightly rearwardly over the body I2 and forwardly to the muzzle end of the choke.

At its forward end the tube I6 is provided with a series of integral ngers 24 which are preferably formed by slotting the forward end of the tube. Each nger is provided with a gas passage 26 and the entire group of fingers is cut away to form a depression 28, the rear end of which is a substantially plane surface normal to the bore of the gn while tnerorward end of the I depression constitutes a cam surface 30 disposed at an acute angle to the bore.

Seated in the depression 28 are opposed gas actuated camming segments 32 and 34 which together comprise an axially movable cam sleeve which cooperates with the surface 30 to move the spring fingers 24 together as hereinafter described. As shown in Fig. 6 the cam members 32 and 34 are hollowed at the rear end to form a gas receiving chamber 36 and are provided with axial passagesv 38 which` register with the passages 23 to provide a complete gas channel extending from the enlarged expansion chamber in the shutter sleeve I6 through to the muzzle end of the choke.

In operation the charge leaves'the gun barrel I0 land moves forwardly into the choke. 'I'he following gas chargeexpands rapidly inside the choke body. A portion of the gas is vented through the openings I4 While an additional portion is diverted through passages 26 to the annular chamber 36 at the rear of the cam members 32 and 34. The cam members are thus forced forwardly by the gas and act to move the spring fingers 24 together by camming the parts together and closing the intervening slots which define the sides of the fingers. The action takes place rapidly as the shot reaches the finger area and the string of shot is thus diametrically compressed as it passes the temporarily depressed fingers and issues from the muzzle in a com'- pacted group. As the shot issues from the muzzle it is followed and surrounded by a sheath of -gas issuing from the passages 2B in the fingers 24. It has been found that the penetrating power of the shot is materially increased and the pattern thereof made more uniform and easily controllable.

It is apparent that the quantity of gas diverted to enter the passages 26 and cause the cam members 32 and A34 to move together is controllable by opening and closing the vents I4 so that a greater or less choking action and penetrating power is imparted to the string of shot. `The expansion chamber formed by the enlarged interior of the shutter sleeve I6 and body I2 is, of course, made controllable in its action by the vents I4 so that the degree of utilization of the expanded gas in imparting increased velocity to the shot string can be fixed by the user. If a less penetrating, more widely scattered string is desired the vents i4 may be opened releasing to a degree the force of the expansion which takes place in the expansion chamber. If a. highly penetrating shot string is desired the vents may be almost completely closed so that the vfull force of the gases burned in the chamber formed by the interior of the shutter sleeve are used to propel x and sheath the string. r

While the present invention has been described in connection with a particular form and disposition of the parts in the two modifications, it will be appreciated that numerous other modiilcations and changes will suggest themselves to those skilled in the art and that such modiiications and changes form a part of the invention as defined in the appended claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent, is:

1. A shotgun choke comprising means providing an expansion chamber ahead of the normal barrel of a shotgun, said expansion chamber having venting openings in its wall, a plurality of resilient fingers carried by said means and cooperating to form a restricted bore ahead of said expansion chamber, gas passages in certain of said fingers, an axially movable annular cam sleeve surrounding said resilient iingers and having a plurality of passages therethrough which the cam sleeve back into position after firing the gun, and means to adjust the relative quantity of gas passing through said vent openings and said passages to determine the degree of bore restriction imparted to said ngers.

2. A shotgun choke comprising a vented expansion chamber ahead of the normal barrel of a shotgun, a sleeve rotatably mounted within the expansion chamber and threadedly engaging said chamber for axial movement therein, said sleeve having a plurality of vents movable into and out ot alignment with the vents in the expansion chamber 4wall to vary the amount of gas passing therethrough, a lplurality of resilient lingers at one end of the sleeve and cooperating to form a restricted bore ahead of said expansion chamber, gas passages in certain kof said iingers extending from said expansion chamber through the outer ends of said iingers, axially movable cam means having passages in alignment with said gas passageways in the ngers, said cam means being adapted to be moved forwardly by the pressure of gas on its rear face, and a cam surface on said lingers adapted to engage said cam means upon the forward movement of said cam means to vary the diametral .position'of the fingers.

WILLIAM F. SCHMELING.

v REFERENCES CITED The following references are of record in the file oi.' this patent:

UNITED STATES PATENTS Whedon Mar. 18, 1947 

